World 2 - Level 2 - The Cloud Bridge

Jump over the fiery pit to get the key. Use it to unlock the door.

Climb the ladder and jump onto the first cloud; it will carry you to the first puzzle piece.

On the second set of clouds, jump across to reach the second puzzle piece above the second cannon.

To get the third puzzle piece, you'll need a specific table-shaped piece from the next level. Once obtained, enter puzzle mode (B button) and position the table piece so it's level with the ledge the monster is on. Exit puzzle mode to check. When the monster walks onto it, quickly enter puzzle assembly mode (B button) and move the piece down and slightly over so the monster gets stuck on the created ledge. Climb the ladder to the left ledge, jump to the smaller ledge, then onto the monster's head to reach the right ledge and the third piece. Alternatively, wait until you have the second table piece and place it midway between the ledges to jump across.

To get the fourth puzzle piece, exit and re-enter the level. Follow the monster walking towards the door. As it passes under the piece above the door, jump on the monster to grab the fourth piece.